Nethula was taken on the recent tours to the West Indies and India but couldn't force his way in to the playing XI for a test and after Jeetan Patel showed some promise when he was recalled for the trip to India the 29-year-old Nethula was pushed out of the mix.
Left-armer Daniel Vettori is also unavailable due to an Achilles injury, which has presented New Zealand coach Mike Hesson with the chance to blood some new talent in the two-test series that will be played after one Twenty20 and five one-dayers.
Astle said he hoped to make an impact in Sri Lanka where he played for the New Zealand under-19 team at the youth World Cup in 2006.
"I sort of look at my stats; 55 first-class games now and the last couple of years has been a transformation,'' he said.
"I started out my career as an opening batsman and in the last couple of years it's been more as a bowler.''
Hesson said Astle had shown he was worthy of a place in the national side through solid efforts at provincial level.
"Todd's been very consistent during the last four or five years in the three facets of the game. Started out as an opening batsman, so obviously he's got plenty of skills there, very good in the field and with the ball he's been a consistent performer winning games in the fourth innings over the last two or three seasons so he earns his opportunity,'' Hesson said.
Astle will be joined in the test squad by the returning Rob Nicol, while BJ Watling isn't included from the group who met India in a quest to give him playing time at Plunket Shield level with Northern Districts.
In the one-day and Twenty20 squad, Doug Bracewell and Martin Guptill have been rested to give them an opportunity to play domestic cricket ahead of the test series.
Trent Boult, Andrew Ellis and Tom Latham are the new faces to the coloured-clothing squad who didn't play in the recent world Twenty20 tournament that was also contested in Sri Lanka.
Ross Taylor will again captain New Zealand.
The tour begins with the sole Twenty20 encounter in Pallekele on October 30.
Twenty20 and one-day squad: Ross Taylor (captain), Trent Boult, Andrew Ellis, James Franklin, Roneel Hira, Rob Nicol, Tom Latham, Brendon McCullum, Nathan McCullum, Kyle Mills, Adam Milne, Jacob Oram, Tim Southee, BJ Watling, Kane Williamson
Test squad: Ross Taylor (captain), Todd Astle, Trent Boult, Doug Bracewell, Daniel Flynn, James Franklin, Martin Guptill, Chris Martin, Brendon McCullum, Rob Nicol, Jeetan Patel, Tim Southee, Kruger van Wyk, Neil Wagner, Kane Williamson